1. Another person or two or three. Yes they can be counted as an equipment packer.
2. Rifle, obvious. Backup left at camp or on the back of your third person.
3. Kestrel 4000
4. Range Cards
5. Ballistics Computer
6. Vectronix Terrapin, backup Leica 1600
7. Ear plugs, don't forget these if you are shooting an ear drum breaker.
8. Elevation builders for rifle rest packed in the backpack
9. GPS with compass